They definitely won't be cramming or cutting corners testing to make it release-worthy just to make that arbitrary date/time. That's what the last few weeks have been for, while 50% of the jailbreaking world have been spewing childish insults on their (dev team's) blog and elsewhere while demanding jailbreak NAOW. And if they are anywhere near as accomplished hackers/programmers as they seem to be, they have already been through extensive testing to make sure the released program will cause as few problems as possible but also be on point to fix any issues that do arise.
That being said, I'm probably going to wait a few days before attempting the JB to watch the process for bugs that appear and maybe see some fixes. Also to get an ETA on an unlock.